EPS

In a first for the province of Nova Scotia, a waste recycling agency has launched a curbside recycling program for expanded polystyrene (EPS) foam, turning waste foam into blocks of condensed material that can be sold to manufacturers and turned into new products.
Two years in the making, the program got off the ground in mid-November, according to an article in the The Kings County Advertiser and Register.

At the Passivhaus job site in Falmouth, Massachusetts, architect Steve Baczek specified the installation of 10 inches of EPS under the slab-on-grade foundation. After the concrete had been placed, more rigid foam was installed above the slab, to bring the finished floor assembly to R-50.

Exterior wall insulation? That usually means rigid foam and furring strips — although occasionally, it means mineral wool insulation and furring strips.
But there are other options. Two new products offer builders new ways to keep their wall sheathing warm.

I recently visited a job site on the outskirts of Berlin that had previously caught my eye. Although the buildings were shrouded in the usual scaffolding and screening, I had noticed while biking by that the work involved “energetische sanierung,” or energy retrofitting.

Researchers have known for years that most types of insulation — including fiberglass batts, extruded polystyrene (XPS), and expanded polystyrene (EPS) — perform better at low temperatures than high temperatures. The phenomenon was described by Chris Schumacher, an engineer and researcher at Building Science Corporation, at a conference in 2011: “If you measure the R-value of an R-13 fiberglass batt, you’ll get different results at different outdoor temperatures. If the outdoor temperature rises, the R-value goes down.

[Editor's note: Roger and Lynn Normand are building a [no-glossary]Passivhaus[/no-glossary] in Maine. This is the 21st article in a series that will follow their project from planning through construction.]

There are many construction and insulation approaches which allow a builder to create walls and ceilings with high R-values and low levels of air leakage, creating a much better envelope than is achieved with standard framing methods. Structural insulated panels (SIPs), insulated concrete forms (ICFs), double-stud walls, and advanced framing can all produce more energy-efficient buildings than the ol' stick-built number.
The one thing they can’t do is to improve the efficiency of an existing house.

As readers of this blog know, I’ve come down fairly hard on certain types of foam insulation over the years. The downsides include the blowing agents used in extruded polystyrene (XPS) and most closed-cell spray polyurethane foam and the flame retardants that are added to all foam-plastic insulation to impart some level of fire resistance.

What’s the best way to install foam insulation on the outside of a wall?
Although GBA has published many articles and videos on the topic, we continue to receive frequent questions from readers asking how to install rigid foam sheathing on exterior walls.
My conclusion: it’s time to provide a primer on the topic.

In the U.S., designers of cutting-edge superinsulated homes generally recommend 2 to 6 inches of rigid foam insulation under residential slabs. For builders who use extruded polystyrene (XPS), the most commonly used sub-slab insulation, that amounts to R-10 to R-30.